SR20 Idles Horrible cold/at 1st start up.then Fine.Help - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

MrFairlady · 04-10-2012, 09:28 PM

Recently My cars(S14 with redtop SR) Gotten worse when 1st starting up Cold from sitting overnight or 4-7+/- hrs.
Only new Item installed is a Blitz VD Blow off valve kit.(Recirc Kit ordered yesterday to help) but even before I ran No Blow off it did it.

** Its never had much of a Cold idle (like my other S13) - More on that.
----------------------------------------
::::1st start Up it idles (1300-1400rpms) ok for about 5-7 sec's and then A/F's go lean,RPMS drop and nearly stalls. It will Just Stay alive and Then idle up a bit,..couple sec's again and it tries to stall again.Pressing the gas it tries to wake up but struggles when gas is given..then revs back up to 1400+/- and Then finally stabilizes 1000rpms and Its Good from there for the most part. it and takes about 2-3 cycles of this above and then its good.
**Only When Starting it up after sitting for a bit.

My car has Never had much of a Fast/cold Idle Bump since its been running so I have no clue where to start next.

Diagnosis:
TPS is set (my 1st thought)...timing is set,No vac leaks,Tried 2 diff Z32 Maf's, but the IACV...well I'm not sure. I feel like that and maybe the Coolant temp sensor may be the culprit but No Codes for either using datascan.Not sure how to Test the IACV to know what to look for.

With the Blowoff installed I do occasionally get the bog/low idle when coming to a stop after driving for a while but not all the time.Recirc ordered.

Enthalpy Tuned ECU for my Setup:
Redtop 2871,850cc Sard injectors,tomei Pon 256,Z32 Maf,Apex'i intake,Walbro,Tomei FPR,FMIC with S14 Blitz VD Pipe kit(new) No leaks,Runs Fine Otherwise.
S13 SR to S14 chassis Wiring Specialties harness also.

Only thing I can think and have noticed is that outside temp affects This.when it was colder out,it didn't seem to be this way,but now that its warmer A.M & P.M now Its an everyday occurrence.Thought air Knock off HKS Style Filter I had was the Issue back in JANUARY, since removing the Filter entirely It was Perfect but you couldn't drive it due to it being SO RICH,..so i bought an Apex'i Power filter Months ago.Seemed to help a little.

any help??

Is the car supposed to Idle at 15degrees because datascan shows 9 when Idling at 1000-1100. I can hit Perform idle mode and boom: 15degrees.

Though I still can't get the idle Below that or it runs somewhat rough.

str33tpr3p · 04-11-2012, 01:45 PM

same thing happens to me on occasion and i have no clue what it is..

rmc4au · 07-06-2014, 01:05 AM

Ever resolve the issue? My car is doing the same.

KoukiMonsta · 07-06-2014, 10:29 AM

start with CTS, cheap and easy to swap.

ultimateirving · 07-06-2014, 11:17 AM

True but iacv also could be sticky

rmc4au · 07-08-2014, 11:27 PM

Changed CTS as well as every other sensor other than MAF and IACV. But the car does studder when revving in neutral.

Kingtal0n · 07-09-2014, 03:09 PM

If tapping the throttle does not assist the problem then you have a fuel delivery issue.

Start with the simple things that are quick and easy. fuel pressure. Injector O-rings. swap the computer. unplug the maf and start it.

Something will stand out as being related. Right now I would just say it's pretty obvious your computer, being a rom tune, is just not tuned well enough for the cold situation.

Cold start tunes with all of those modifications tend to be trial and error over a period of a few days. You start it, take notes, make changes to the tune. Wait till the next day. Start again, take notes, make changes. Rinse and repeat until it runs right.

there are bandaids though. If the A/F is truly lean, then make a small boost leak. You can run a vacuum line from the intercooler plumbing to the inside of the car. Open it up when you start, engine gets more fuel, problem solved. Plug it with a screw once she warms up.

Gota think like the computer if you can't make changes to it.

rmc4au · 07-09-2014, 11:09 PM

Maf is good. AFR's are normal. Fuel pressure is good. Swapped computers. New wiring harness. Been dealing with the studder since December.

venom2034 · 07-10-2014, 07:33 AM

i had way too many problems with enthalpy tunes. the idle was way too lean, almost like your symptoms and I could never figure it out.

Kingtal0n · 07-10-2014, 11:08 AM

Quote:

Originally Posted by rmc4au

Maf is good. AFR's are normal. Fuel pressure is good. Swapped computers. New wiring harness. Been dealing with the studder since December.

You only need fuel spark air.

If adding air doesn't help (stepping on the throttle) then its...

fuel. If adding fuel doesnt help (richen up the mixture) then its....

spark. put some new spark plugs in it and start changing ignition components (after plugs, igniter, coil harness, coils, etc....)

Sounds like fuel though.

04-10-2012, 09:28 PM	#1
MrFairlady Nissanaholic! Join Date: Mar 2007 Location: Fascination Street,N.C Age: 42 Posts: 1,701 Trader Rating: (31) Rides Gallery: MrFairlady Feedback Score: 31 reviews	SR20 Idles Horrible cold/at 1st start up.then Fine.Help Recently My cars(S14 with redtop SR) Gotten worse when 1st starting up Cold from sitting overnight or 4-7+/- hrs. Only new Item installed is a Blitz VD Blow off valve kit.(Recirc Kit ordered yesterday to help) but even before I ran No Blow off it did it. ** Its never had much of a Cold idle (like my other S13) - More on that. ---------------------------------------- ::::1st start Up it idles (1300-1400rpms) ok for about 5-7 sec's and then A/F's go lean,RPMS drop and nearly stalls. It will Just Stay alive and Then idle up a bit,..couple sec's again and it tries to stall again.Pressing the gas it tries to wake up but struggles when gas is given..then revs back up to 1400+/- and Then finally stabilizes 1000rpms and Its Good from there for the most part. it and takes about 2-3 cycles of this above and then its good. *Only When Starting it up after sitting for a bit. My car has Never had much of a Fast/cold Idle Bump since its been running so I have no clue where to start next. Diagnosis: TPS is set (my 1st thought)...timing is set,No vac leaks,Tried 2 diff Z32 Maf's, but the IACV...well I'm not sure. I feel like that and maybe the Coolant temp sensor may be the culprit but No Codes for either using datascan.Not sure how to Test the IACV to know what to look for. With the Blowoff installed I do occasionally get the bog/low idle when coming to a stop after driving for a while but not all the time.Recirc ordered.* Enthalpy Tuned ECU for my Setup: Redtop 2871,850cc Sard injectors,tomei Pon 256,Z32 Maf,Apex'i intake,Walbro,Tomei FPR,FMIC with S14 Blitz VD Pipe kit(new) No leaks,Runs Fine Otherwise. S13 SR to S14 chassis Wiring Specialties harness also. Only thing I can think and have noticed is that outside temp affects This.when it was colder out,it didn't seem to be this way,but now that its warmer A.M & P.M now Its an everyday occurrence.Thought air Knock off HKS Style Filter I had was the Issue back in JANUARY, since removing the Filter entirely It was Perfect but you couldn't drive it due to it being SO RICH,..so i bought an Apex'i Power filter Months ago.Seemed to help a little. any help?? Is the car supposed to Idle at 15degrees because datascan shows 9 when Idling at 1000-1100. I can hit Perform idle mode and boom: 15degrees. Though I still can't get the idle Below that or it runs somewhat rough. __________________ z-tERty-2

07-06-2014, 11:17 AM	#5
ultimateirving Zilvia FREAK! Join Date: Nov 2010 Location: arizona Age: 33 Posts: 1,519 Trader Rating: (1) Feedback Score: 1 reviews	True but iacv also could be sticky __________________ Z32 with lq4 swap Desert Street Scene \|\| Dssevents.com

07-09-2014, 03:09 PM	#7
Kingtal0n Post Whore! Join Date: Jul 2005 Location: South Florida Age: 38 Posts: 4,649 Trader Rating: (17) Feedback Score: 17 reviews	If tapping the throttle does not assist the problem then you have a fuel delivery issue. Start with the simple things that are quick and easy. fuel pressure. Injector O-rings. swap the computer. unplug the maf and start it. Something will stand out as being related. Right now I would just say it's pretty obvious your computer, being a rom tune, is just not tuned well enough for the cold situation. Cold start tunes with all of those modifications tend to be trial and error over a period of a few days. You start it, take notes, make changes to the tune. Wait till the next day. Start again, take notes, make changes. Rinse and repeat until it runs right. there are bandaids though. If the A/F is truly lean, then make a small boost leak. You can run a vacuum line from the intercooler plumbing to the inside of the car. Open it up when you start, engine gets more fuel, problem solved. Plug it with a screw once she warms up. Gota think like the computer if you can't make changes to it. __________________ 5.3/4l80e/turbo 240sx playthrough: https://tinyurl.com/turbo240

Thread Tools
Show Printable Version Email this Page
Display Modes
Linear Mode Switch to Hybrid Mode Switch to Threaded Mode

04-11-2012, 01:45 PM	#2
str33tpr3p Leaky Injector Join Date: Apr 2012 Location: canada Posts: 56 Trader Rating: (0) Feedback Score: 0 reviews	same thing happens to me on occasion and i have no clue what it is..

07-06-2014, 01:05 AM	#3
rmc4au Join Date: Sep 2013 Location: Auburn, AL Age: 25 Posts: 9 Trader Rating: (0) Feedback Score: 0 reviews	Ever resolve the issue? My car is doing the same.

07-06-2014, 10:29 AM	#4
KoukiMonsta Nissanaholic! Join Date: Mar 2009 Location: NC Posts: 1,969 Trader Rating: (23) Feedback Score: 23 reviews	start with CTS, cheap and easy to swap.

07-08-2014, 11:27 PM	#6
rmc4au Join Date: Sep 2013 Location: Auburn, AL Age: 25 Posts: 9 Trader Rating: (0) Feedback Score: 0 reviews	Changed CTS as well as every other sensor other than MAF and IACV. But the car does studder when revving in neutral.

07-09-2014, 11:09 PM	#8
rmc4au Join Date: Sep 2013 Location: Auburn, AL Age: 25 Posts: 9 Trader Rating: (0) Feedback Score: 0 reviews	Maf is good. AFR's are normal. Fuel pressure is good. Swapped computers. New wiring harness. Been dealing with the studder since December.

07-10-2014, 07:33 AM	#9
venom2034 Zilvia Junkie Join Date: Feb 2011 Location: flushing, Ny Age: 30 Posts: 453 Trader Rating: (10) Feedback Score: 10 reviews	i had way too many problems with enthalpy tunes. the idle was way too lean, almost like your symptoms and I could never figure it out.